From: Jakub Sitnicki jakub@cloudflare.com
mainline inclusion from mainline-v6.10-rc2 commit 98e948fb60d41447fd8d2d0c3b8637fc6b6dc26d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QG7M CVE: CVE-2024-35895
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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We have seen an influx of syzkaller reports where a BPF program attached to a tracepoint triggers a locking rule violation by performing a map_delete on a sockmap/sockhash.
We don't intend to support this artificial use scenario. Extend the existing verifier allowed-program-type check for updating sockmap/sockhash to also cover deleting from a map.
From now on only BPF programs which were previously allowed to update sockmap/sockhash can delete from these map types.
Fixes: ff9105993240 ("bpf, sockmap: Prevent lock inversion deadlock in map delete elem") Reported-by: Tetsuo Handa penguin-kernel@i-love.sakura.ne.jp Reported-by: syzbot+ec941d6e24f633a59172@syzkaller.appspotmail.com Signed-off-by: Jakub Sitnicki jakub@cloudflare.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Tested-by: syzbot+ec941d6e24f633a59172@syzkaller.appspotmail.com Acked-by: John Fastabend john.fastabend@gmail.com Closes: https://syzkaller.appspot.com/bug?extid=ec941d6e24f633a59172 Link: https://lore.kernel.org/bpf/20240527-sockmap-verify-deletes-v1-1-944b372f210... Signed-off-by: Liu Jian liujian56@huawei.com --- kernel/bpf/verifier.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 946e485a102c..c628fe1d105e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4718,7 +4718,8 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) enum bpf_attach_type eatype = env->prog->expected_attach_type; enum bpf_prog_type type = resolve_prog_type(env->prog);
- if (func_id != BPF_FUNC_map_update_elem) + if (func_id != BPF_FUNC_map_update_elem && + func_id != BPF_FUNC_map_delete_elem) return false;
/* It's not possible to get access to a locked struct sock in these @@ -4729,6 +4730,11 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) if (eatype == BPF_TRACE_ITER) return true; break; + case BPF_PROG_TYPE_SOCK_OPS: + /* map_update allowed only via dedicated helpers with event type checks */ + if (func_id == BPF_FUNC_map_delete_elem) + return true; + break; case BPF_PROG_TYPE_SOCKET_FILTER: case BPF_PROG_TYPE_SCHED_CLS: case BPF_PROG_TYPE_SCHED_ACT: @@ -4816,7 +4822,6 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, case BPF_MAP_TYPE_SOCKMAP: if (func_id != BPF_FUNC_sk_redirect_map && func_id != BPF_FUNC_sock_map_update && - func_id != BPF_FUNC_map_delete_elem && func_id != BPF_FUNC_msg_redirect_map && func_id != BPF_FUNC_sk_select_reuseport && func_id != BPF_FUNC_map_lookup_elem && @@ -4826,7 +4831,6 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, case BPF_MAP_TYPE_SOCKHASH: if (func_id != BPF_FUNC_sk_redirect_hash && func_id != BPF_FUNC_sock_hash_update && - func_id != BPF_FUNC_map_delete_elem && func_id != BPF_FUNC_msg_redirect_hash && func_id != BPF_FUNC_sk_select_reuseport && func_id != BPF_FUNC_map_lookup_elem &&